Thread: Td5 Hi-Lo and Maps

with significant vibrations between a certain rev range and load.

If at 2100RPM, they all do that at some time and its the handbrake shoes against the backing plate. maybe also engine mounts.

The Hi lo control is manual , so someone has connected it incorrectly on the transfer .
The hi/lo switch perhaps is not adjusted correctly. You can test with a multimeter across the switch terminals to see if it changes when the lever is is high or low. AFAIR they are adjustable with a thread and locknut. The actuator if like the diff lock switch just runs up a ramp on the selector shaft. I am talking the switch rather than the wires.

I am surprised that with EGR delete and mods that the engine is unresponsive as mine admittedly a 2002 is very responsive with similar mods feeling like a V8 in initial acceleration.
What about errors in the ECU? Are there any?
Has anyone had the head off? as could be timing a cog out.
Regards PhilipA

I think the hi and lo reading maybe just a glitch in the nanocom reading. If I remember correctly I think they all read this way. I'll check on mine when I get a chance.

Just a note with cruise control, the Nanocom will let you test the actual input from the steering wheel mounted controls. My cruise control isn't working at the moment because the "set" button isn't getting the signal back to the controller.

Also, the hi/low switch is mounted in the transfer case and your range lever would be appeared to have been re-installed backwards as it would be difficult, I think, to reverse the operation at the transfer case. In this instance, the switch output should correctly reflect the actual transfer case range position.

can't really help with performance issues, but what air flow readings are you getting via the nanocom?
Bad/faulty/ or cheapo MAFs can cause issues. Disconnecting can reveal something.

At what revs do you get lockup? Weird that it's gutless not locked, and then feels fine when locked.

As for the CC .. obvious stuff.. do the brake lights work? Don't assume that they do, confirm it.
And, if they do work, are they quick responsive like LED lights are? ie. has someone installed LEDs for all 3 brake lights.

Cruise control systems, unless designed for them, don't like LEDs. They need to confirm that the brake's electrical system needs to be operational for the CC to work.
I've found this the hard way.
On my D1, I fitted an aftermarket CC, but had std globes for the tail/brakes .. had many tails or brake globes blow out, and they are a PITA to get too(just a decent idea, done badly).
Anyhow, I replaced the two main globes to LEDs, and had a spare cheapo LED that fitted perfectly into the high mount globe too. awesome!(so I thought) .. but the pretty new CC started to play funny buggas, and then stopped completely.
Checked cables and wires and stuff .. and no dice. The one day doing something randomly different(maybe washing dishes) the penny dropped. I pulled the highmount LED brake globe and replaced it with a std single pole brake light globe .. CC worked perfectly again.
Even tho the D1 is not canbus, it still needed canbus type globes for it to light the LED tails and brake diodes. Otherwise a resistor is needed across the power path for each globe.

Readings..

Using Nanocom (with revision 1.35)

Engine inputs > Transfer Ratio - High = High
SLABS inputs > Low Range Switch - High Range = open / Low Range = closed
Trans > High/Low Switch - High = closed

Using Hawkeye Total

Engine inputs > Gearbox Switch - Trans High = low / Trans Low = high
Trans Input > High/Low Range - High = high / Low = low

Maybe Nanocom has changed the way it reads after recent revisions and is reading correctly now.

Can you read the Part No. for the Trans Controller with your Nanocom? It should be UHC 100 250 for '99 TD5 Auto.
It's just another check to make sure somebody hasn't put the wrong one in there.

My vehicle is '99 TD5 Auto w/ stage 2 tune, HD torque converter etc etc... but with a V8 trans controller.

Originally Posted by mylesaway

Can you read the Part No. for the Trans Controller with your Nanocom? It should be UHC 100 250 for '99 TD5 Auto.
It's just another check to make sure somebody hasn't put the wrong one in there.

My vehicle is '99 TD5 Auto w/ stage 2 tune, HD torque converter etc etc... but with a V8 trans controller.

IGG 100 010 should be the correct TCU for early Td5 auto with the 83 km/h lock up in 4th ?

Originally Posted by smOke

I decided to unplug the hi-lo switch on the transfer and see if I'd get different readings. With the switch disconnected it now reads in Td5 Engine Inputs 'high' when in both hi and lo range and in SLABS the transfer reads 'open' when in both hi and lo.
I understand the switch works as an earth but have no idea how it talks to the ECU and SLABS and ETA.

Would the above Nanocom readings suggest that the switch is working and communicating the correct transfer ratio to SLABS but the ECU is always reading the ratio as low range? Thus the pedal and fuel map is incorrect when in high range? Would this influence gear shift points too?
If this is the case, could the hi-lo wire to the ECU be earthing somewhere? ie. the fact that it reads 'high' in both hi and lo when the switch is connected and disconnected.

I'm at the end of my tether with this vehicle. Any input would be greatly appreciated.
Thanks.

When I last checked by disconnecting the switch, and also looking at fuel maps, the switch earths the 3 units at same time, so regardless of test equipment readings, physically it is open circuit in high range and short circuit to earth (via a return path in the loom) in low range, basically adjusting the foot pedal so you have to use zero to full travel when in low range and zero to only 60 % travel gives you full throttle in high range.

Can you borrow someones ecu to swap out and eliminate that as a problem ?

Originally Posted by smOke

I've been chasing a performance issue for some time now and am no closer to resolving it despite trying a lot of options.
99 Auto Td5 – Stage 2 map, uprated intercooler, silicon hoses, EGR delete, centre silencer removed, snorkel, CDL conversion (with relevant wire cut at SLABS for ABS , TC and HDC).

The Disco just drives poorly until in 4th lockup – then it seems to pull and hum along. Anything under that is a real flog of the pedal (especially up hill or under load) with significant vibrations between a certain rev range and load. It has strange shift points – it seems to hang in gear too long and gives a good kick in the behind when changing. Cruise control has never worked.
I've done most of the usual things you'd expect. Have replaced most sensors, checked turbo actuator, tested intercooler, smoke tested, checked fuel pressure etc.
I had thought the issue (perhaps ONE of the issues) was a wiring problem with an earth problem or chaffed loom.

Most recently my mechanic concluded it must be torque converter and/or transmission. Reluctantly, I had the transmission dropped. It turned out the torque converter and transmission were in bad shape so were overhauled.
However after reinstalling the difference is marginal. The Disco still presents most of the initial problems. It's gutless (unless in 4th lockup), weird gear changes and vibrates like mad.
Now, for some bizarre reason, the hi-lo lever is backwards! So hi range is in the forward position and lo range is back towards the gear shifter. Cruise Control still no longer works which I was expecting to resolve itself. The brake switch in Nanocom reads correctly.

I've had my Nanocom out trying to see if I can find any clues. On checking the hi-lo settings in Td5 Engine Inputs it was reading 'high' when in both hi and lo range. I understand 'high' actually translates to 'low'?
In SLABS the transfer would read 'open' when in hi and 'closed' when in lo.
I decided to unplug the hi-lo switch on the transfer and see if I'd get different readings. With the switch disconnected it now reads in Td5 Engine Inputs 'high' when in both hi and lo range and in SLABS the transfer reads 'open' when in both hi and lo.
I understand the switch works as an earth but have no idea how it talks to the ECU and SLABS and ETA.

Would the above Nanocom readings suggest that the switch is working and communicating the correct transfer ratio to SLABS but the ECU is always reading the ratio as low range? Thus the pedal and fuel map is incorrect when in high range? Would this influence gear shift points too?
If this is the case, could the hi-lo wire to the ECU be earthing somewhere? ie. the fact that it reads 'high' in both hi and lo when the switch is connected and disconnected.

I'm at the end of my tether with this vehicle. Any input would be greatly appreciated.

Thanks.

I recently replaced the pressure can in my 2002 Defender TD5 fuel pressure regulator as the original was leaking from this item and I did not see the need for replacement of the fuel regulator complete. I had previously fitted a pressure gauge to keep an eye on fuel pressure and prior to my replacement of this part it was consistently reading around 60psi at all revs. After I replaced this can purchased for around $40 on ebay for a quality German made replacement part the new pressure is now consistently 90psi at all revs and now the engine pulls like a train in comparison to the old original. I am surprised the electric fuel pump can achieve this pressure but I have been running this setup for around twelve months now while towing a 3.2 ton off-road caravan. Try replacing this part on your TD5 fuel regulator and I am sure will get the engine performance designed by the factory. I will try and find the part number of the part I replaced so others can do the same.